1. Field of the Invention
The present invention relates to a steering column for a vehicle, and more particularly to a steering column for a vehicle which can increase the entire strength of the steering column while maintaining a supporting force between an outer tube and an inner tube at the time of tightening or releasing an adjusting lever for a tilting or telescopic operation, thereby preventing deformation and breakage of the steering column when a driver operates a steering wheel.
2. Description of the Prior Art
As generally known in the art, a steering column refers to a device for enclosing a steering shaft which transfers a rotational force generated when a driver operates a steering wheel to a rack and a pinion mechanism, in which the steering column supports the rotation of the steering shaft and is secured to a vehicle body through a bracket to fix the position of the steering column.
The steering column as mentioned above may further include a telescopic or tilting function for enhancing the driver's convenience. The tilting device is designed to adjust the fixing angle of the steering wheel. The telescopic device is formed by inserting two hollow tubes which can be axially extended or retracted, and has a function to absorb the shock energy by collapsing the steering shaft and the steering column when the vehicle is crashed.
Therefore, the steering device may be divided into a telescopic type or a tilting type steering device according to the function as mentioned above. Depending upon the case, a tilting function may be added to the telescopic type steering device. Hence, the driver can make a smooth steering operation by adjusting the projecting amount or tilting angle of the steering wheel which corresponds to his/her height or body shape using the above functions.
FIG. 1 is an exploded perspective view illustrating a portion of a steering column for a vehicle in the prior art.
As shown in FIG. 1, the conventional steering column for the vehicle, including: an outer tube 100 for receiving a steering shaft 175; an inner tube 170 inserted in the outer tube; a lower mounting bracket 165 for fixedly securing the inner tube 170 to a vehicle body; a upper mounting bracket 105 disposed over the outer tube 100 and secured to the vehicle body; a distance bracket 180 integrally fixed to the outer tube 100 and formed with a telescoping elongated hole 185; a tilting bracket 150 integrally formed with the upper mounting bracket 105 and provided with a tilt elongated hole 110; a fixed gear 145 formed on the outer side of the tilting bracket 150; a movable gear 140 detachably engaged with the fixed gear 145; a tilting bolt 130 penetrating through the tilt elongated hole 110; a cam 135 engaged with the movable gear 140; a washer 125 and a nut 120 for securing the cam 135 and an adjusting lever 115; and a spring 142 retained between the movable gear 140 and the fixed gear 145.
The tilting or telescopic operation is performed by tightening or releasing the adjusting lever 115. When the adjusting lever 115 is tightened by the driver, the tilting bracket 150 is narrowed to exert a pressure on the outer tube 100, and then the outer tube 100 is in close contact with the inner tube 170 to prevent the tilting or telescopic operation. In contrast, when the adjusting lever 115 is released by the driver, the pressure applied between the outer tube 100 and the inner tube disappears to make the tilting or telescopic operation available.
Here, the telescopic operation is performed by firstly releasing the adjusting lever 115, changing the position of the tilting bolt 130 along the telescoping elongated hole 185 formed at the distance bracket 180, and then tightening the adjusting lever 115 again to complete the telescopic operation.
On the other hand, the tilting operation is made by releasing the adjusting lever 115, changing the position of the tilting bolt 130 along the tilt elongated hole 110, and finally tightening the adjusting lever 115 to complete the tilting operation.
In a state that the adjusting lever 115 is locked, the outer tube 100 and the steering shaft 175 or the like are firmly fixed. However, when the adjusting lever 115 is released, the outer tube 100 and the inner tube 170 or the like can be tilted about the center 160 of tilting movement by the cam 135, or the steering column can be extended or retracted accordingly.
However, the conventional steering column for the vehicle as described above has drawbacks that a load is concentrated on the tilting bracket and the distance bracket which is designed to tighten the steering column through the tilting bolt and the adjusting lever, which weakens the supporting force for the steering column and the strength of the steering column itself.
Particularly, the conventional steering column for the vehicle still has drawbacks in that the connecting portion between the outer tube and the tilting bracket to be secured to the vehicle body through the mounting bracket is weak and reduces the overall strength of the steering column itself, compared with the steering column supporting force. Moreover, the steering column is deformed or broken due to a torsional load generated when the driver operates the steering wheel, and is seriously bent at the time of collision of the vehicle.